A day after arriving in the Iranian capital, the IAEA's Rafael Grossi opened discussions with the chief of the Atomic Energy Organization of Iran, Mohammad Eslami, the official news agency IRNA said.

Later, he was to meet for the first time with Foreign Minister Hossein Amir-Abdollahian, who is in charge of nuclear issues in Iran's new government.

The talks come ahead of the scheduled resumption next Monday of negotiations between Tehran and world powers aimed at saving the 2015 deal that gave Iran sanctions relief in return for curbs on its nuclear programme.

Hours before Grossi's arrival, Iran's foreign ministry spokesman Saeed Khatibzadeh expressed hopes that his visit would be "constructive".

"We have always advised the IAEA to stay on the path of technical cooperation, and to not let certain countries pursue their political orientations on behalf of the IAEA," he said.

Grossi's visit comes after the IAEA said last Wednesday that Iran had boosted its stockpile of highly enriched uranium to 2,489.7 kilograms -- many times in excess of the limit laid down in the 2015 agreement.

Iran began easing its commitments under the deal in 2019, a year after then president Donald Trump unilaterally withdrew the United States from the accord and began imposing crippling sanctions.

Trump's successor Joe Biden wants to bring Washington back into the agreement known as the Joint Comprehensive Plan of Action, or JCPOA.

Tehran is demanding all sanctions imposed or reimposed on it by the US since 2017 be lifted.

The November 29 talks will be held in Vienna, where the IAEA is based.

The remaining parties to the deal -- Britain, China, France, Germany and Russia -- will join the talks while the United States will participate indirectly.